Electric switch



F. G. RAWLINGS ANDA; H. McDANlEL. ELECTRIC SWITCH.

APPLICATIONI FILED DEC. 3l 1918. 1,831,783. Patented Feb. 24,1920.

UNITED STATES PATENT OFFICE..-

FREDERICK Gr. RAWLINGS AND ALEXANDER II. MCDANIEL, OF WILMINGTON, DELA- WARE, ASSIGNORS TO ATLAS POWDER COMPANY,

CORPORATION OF DELAWARE.

OF VTILMINGTON, DELAWARE, A

ELECTRIC SWITCH.

Specification of Letters Patent.-

Patented Feb. 24, 1920.

Application filed December 31., 1918. Serial No. 269,149.

To all whom t may concern:

Be it known that we, FREDERICK Gr. RAW Lines and ALEXANDER H. MCDANIEL, citizens of the United States of America, residing at Wilmington, Castle and State of Delaware, have invented certain new and useful VImprovements in Electric Switches, of which the following is a specification.

This invent'on relates to electric switches and inore'particularly toan oil-switch constructed in such manner as to render it possible to safely make or break a circuit carrying a high' volta e electric current. The

most important object of the invention is the provision of such a construction `as will make it possible to open or close the switchV with a straight pull or push. In other words, the necessity of swinging an operating handle upon the arc of a circle is avoided and this materially contributes to the safety of the operator because in swinging the handles of large knife-blade switches upon an arc there is always the possibility that the hand of the operator will slip from the handle of the switch and come into contact with one of the terminals, with fatal results.

As this description proceeds it will be seen that the simplicity and economy of the knife-blade switch have been retained but that operating elements have been provided, of such nature that the operating handle moves in a straight line and liesoutside of an oil-tight casing in which the knife switch is mounted for movement in an oil bath.

A switch embodying one form of the invention is illustrated in the accompanying drawing in whic Figure 1 is a vertical section; and

Fig. 2 a transverse section.

Like numerals designate corresponding parts in both of the figures of the drawing.

Referring to the drawing, 5 designates a cast-iron casing having a cover 6 that is held in place by screws 7. The casing 5 is provided with integral ribs 8 and lugs 9 which constitute a seating for the base 10 of a knife-blade switch. A sheet metal clamp 11 is secured to the casin by screws 12 and engages the upper edge o the switch to hold the same securely in place. `It is to be noted that the ribs 8- are of such shape as to support the switch at an angle, or in an in the county of New4 inclined position. It will of course be understood that the switch may comprise as many blades as is desired. The switch shown in the drawing comprises three blades 13, 14 and 15 that are pivoted respectively to contacts 16, 17 'and 18 and are adapted Yto make and break connection with contacts 19, 20 and 21. Conductors 22l lead from the contacts 16, 17 and 18 to an insulating block 23 of slate or other suitable insulating material and conductors 24: lead from the con-V tacts 19, 20 and 21 to a like insulating block 25 and the ends of the conductors 22 and 21 are connected to suitable terminals 26 upon the insulating blocks. Insulating bushings 27 mounted in the walls of the casing 5 provide passages throughwhich conductors indicated at 28 may pass from the blocks 23 and 25 to the exterior of the casing 5.

The blades 13, 14 and 15 are connected by a cross bar 29 that carries a bifurcated bracket 30. A knob 31 of insulating material constitutes an operating handle for the switch. vThis knob is mounted upon a stem 32 that slides through a bearing boss 33 of the casing 5. A flattened portion 34C' of the stem enters between the ears of the bifurcated bracket 30 and is traversed by a pin 35 which also passes through slots 36 formed in said ears. Washers 37 and pins 38 hold the parts in assembled relation.

Since the casing 5 is oiland acid-proof as well as waterproof it may be Iplaced out of doors or in any other location with perfect safety. Since all of the operating parts are completely insulated from the casing 5, it being understood that the bar 29 is of insulating material, as is usual in knife-blade switches, it will be utterly impossible for the hand of the operator to come into contact with any energized part. In use the casing 5 will 'be filled with oil to such level as to submerge the contacts, 19, 20 and 21. This prevents arcing, oxidizing of the terminals and insures that such terminals will always be in condition to make a good contact. By supporting the switch at an angle the contact points are brought into such relation that the circuit may be completed with a minimum of movement of stem 32 and handle 31 in a straight, horizontal line.

While the elements shown and described are well adapted to serve the purposes for which they are intended it is to be understood that the invention is not limited to the precise construction set forth but includes within its purview whatever changes fairly come within the spirit of the appended claims.

Having described our invention, whatwe claim is:

l. The combination with an oil tight cas: ing, of a knife blade switch therein comprising a base disposed at an angle to the vertical, contact elements outstanding from said base, a blade pivoted at one end of its ends to one of said elements and swinging upon an arc therefrom into and out of engagement with the other of said elements and moving to opposite sides of a vertical line through its pivot point, an operating member movable in a straight line through the wall of the casing and a sliding connection between the operating member and the free end of the fblade.

y 2. The combination withan oil tight casing, of integral supporting members carried thereby the bearing surfaces of which are disposed atan acute angle with relation to the vertical7 a knife blade switch comprising an insulating base supported thereby, means carried by the casing' rand engaging' saidbase for holding the same against the bearino' surfaces of said su ortinof mem- 30 bers, said switch comprising a swinging blade carrying part, an operating handle of insulating' material, a stem by which said handle is carried, said stem `beingv slidably mounted in a wall of the casing and a sliding connection between the inner end of said stem and the blade carrying part of the switch. p

3. The combination with an oil tight casing, of a standard knife blade switch carried therein the base of which lies at acute angle to the vertical," a horizontally movable operating member slidably mounted in the Wall of the casing and disposed above the level of the Contact members of theswtch and having operative` connection with the movable member'of the switch, insulating terminal blocks secured to' the op'- posite inner side walls of the casing and permanent connections between said blocks and therespective terminals of the switch.

In testimpny whereofwe affix our signatures in the presence v of twowitness'es.

FREDERlCK Gr. RAWLINGS. ALEXANDER H. MCDNIEL. Witnesses:

vH. B. HYGATE,

C. C. Kms. 

